The mechanism of binding of pyridoxal 5'-phosphate to enzymes is being studied. Kinetic methods, including variations of pH, concentration, buffer, temperature, and other things, are being used. The mechanism of binding provides important insight into the nature of the interactions between the coenzyme and the protein. Similar studies are being made with aspartate aminotransferase. Other studies of glutamate decarboxylase include studies of the pH dependence of the structure of the enzyme, structure changes following pH jump, and the activity of the enzyme with substrate and coenzyme analogs.